Method and composition for washing poultry during processing

ABSTRACT

The present invention relates to compositions including peroxyacetic acid and peroxyoctanoic acid and methods for reducing microbial contamination on poultry. The methods include the step of applying a mixed peroxycarboxylic acid composition to poultry.

FIELD OF THE INVENTION

[0001] The present invention relates to compositions includingperoxyacetic acid and peroxyoctanoic acid and methods for reducingmicrobial contamination on poultry. The methods include the step ofapplying a mixed peroxycarboxylic acid composition to poultry.

BACKGROUND OF THE INVENTION

[0002] All poultry carcasses entering the processing environment arecontaminated with bacteria, some with pathogenic bacteria such asSalmonella. Fecal matter and dirt are the main sources of thiscontamination. As a result of such contamination, poultry is typicallywashed at any of several steps during the process of converting a livebird to an edible food product. Such washing aims to remove dirt, offal,blood, viscera, other debris, and microbes from the poultry. Removing orreducing microbes aids the safe storage and consumption of poultry, yetmany existing washing procedures fail to significantly reduce themicrobe burden on poultry. The potential for poultry skin to becomecross-contaminated is worsened by the ability of all types of bacteria(Gram-positive, Gram-negative, flagellated, non-flagellated, rods orcocci) to adhere within only 15 seconds of contact. Once in theprocessing environment, a significant number of carcasses can becomecross-contaminated with pathogens during handling, scalding, mechanicalprocessing, and chilling. Current methods for many of these proceduresalso fail to significantly reduce the microbe burden on poultry.

[0003] Water used for washing or these other procedures is often usedrepeatedly over time, which provides yet another opportunity spreading,rather than reducing, microbial burden on poultry. For example, thewater becomes contaminated with organic matter and microbes from thepoultry, and the organic matter provides nutrients for microbial growthin the water over time or through additional use. These microbes cangrow on and contaminate additional poultry and processing equipment. Inparticular, water left untreated in a submersion bath tends todecontaminate poultry early in a shift but contaminates poultry later inthe shift. In fact, such water has been identified as a potential sourceof coliform, E. coli and Salmonella contamination or cross contaminationduring poultry processing. Salmonella and other microorganisms aregenerally undesirable to the poultry, the water, and can cause buildupon all water contact surfaces of slime or biofilm, which requiresfrequent cleaning to remove.

[0004] Microbial contamination or cross contamination of poultry viawater continues to be a major concern for poultry processors and endusers. Although washing, cooling, or heating poultry carcasses withwater can reduce potential contamination, the processing water can alsoserve as a source of contamination or cross contamination. If pathogenicmicroorganisms in water are not removed, inactivated or otherwisecontrolled, they can spread to other poultry, potentially contaminatingthem. Further, handling or processing steps that pool many individualpoultry parts tend to increase the risk that a single contaminated itemmay contaminate the entire lot. Immersing or spray-washing poultry infresh water can help reduce surface populations of microorganisms.However sterilization by repeated washing, even with sterile water,cannot be achieved because microorganisms within tissues of poultryremain in place.

[0005] The addition of antimicrobial agents to wash or process water caninactivate vegetative bacteria cells in water, helping avoidcontamination. Ideally, an antimicrobial agent or compound used in sucha system will have several important properties in addition to itsantimicrobial efficacy. The compound or agent should have no technicaleffect on the final food product. Residual activity implies the presenceof a film of antimicrobial material which will continue to haveantimicrobial effect which may require further rinsing of the foodproduct. The antimicrobial agent preferably should also be odor free toprevent transfer of undesirable odors onto food stuffs. If direct foodcontact occurs, the antimicrobial agent should also be composed of foodadditive materials which will not affect food wholesomeness, nor affecthumans should incidental ingestion result. In addition, theantimicrobial agent should preferably be composed of naturally occurringor innocuous ingredients, which are chemically compatible with theenvironment and cause no concerns for toxic residues within the water.

[0006] In the past, poultry wash or process waters have generally beentreated with chlorinated compounds, organic acids, acidified sodiumchlorite, trisodium phosphate, or ozone. Generally, these materials areeffective in reducing microbial contamination on poultry. However, theuse rate of these antimicrobials is very high because they are noteffective at low concentrations or they tend to be rapidly consumed bythe high organic load included with the poultry. Excessive chlorinationof food processing water with hypochlorite has prompted concern overproduction of toxic or carcinogenic organochlorine compounds and otherby-products.

[0007] Further, the efficacy of conventional antimicrobial agents on thesurface of poultry is often limited. For example, it has been reportedthat, generally, concentrations of more than 4 wt-% of organic acids orof 5 to 10 wt-% of trisodium phosphate are required to effectivelyreduce contamination of poultry skin by S. typhimurium. Antimicrobialagents such as peroxides or lactic acid can result in discoloring,bleaching, or bloating of poultry tissue.

[0008] The EPA approved a peroxyacetic acid-based composition in 1996for controlling microbial growth and reducing biofilm formation in fruitand vegetable transport or process waters. From a historicalperspective, peroxyacetic acid has been used for food contact surfacesanitizing, aseptic packaging and medical device cold-sterilization. Inaddition to its biocidal properties, the environmentally-friendlydecomposition byproducts and good stability in the presence of organicmatter helped gain acceptance of this technology among fruit andvegetable packers, handlers, and processors.

[0009] Nevertheless, there remains a need for improved antimicrobialcompositions for addition to waters used for washing or processingpoultry.

SUMMARY OF THE INVENTION

[0010] The present invention relates to compositions includingperoxyacetic acid and peroxyoctanoic acid and methods for reducingmicrobial contamination on poultry. The methods include the step ofapplying a mixed peroxycarboxylic acid composition to poultry. Thecompositions and methods of the invention provide an antimicrobial agentuseful in water for washing or processing poultry, that has a highdegree of antimicrobial efficacy, and that is safely ingestible byhumans while imposing no unacceptable environmental incompatibility.

[0011] A preferred antimicrobial composition of the present inventionincludes acetic acid, octanoic acid, peroxyacetic acid, peroxyoctanoicacid, and hydrogen peroxide. In one embodiment, an antimicrobialconcentrate composition of the present invention includes about 40 toabout 70 weight-% acetic acid, about 2 to about 20 weight-% octanoicacid, and about 5 to about 15 weight-% hydrogen peroxide. In anotherembodiment, the antimicrobial concentrate composition of the presentinvention includes an equilibrium mixture resulting from a combinationof about 40 to about 70 weight-% acetic acid, about 2 to about 20weight-% octanoic acid, and about 5 to about 15 weight-% hydrogenperoxide. In a third embodiment, the antimicrobial concentratecomposition of the present invention includes about 30 to about 60weight-% acetic acid, about 1 to about 15 weight-% octanoic acid, about2 to about 12 weight-% hydrogen peroxide, about 6 to about 16 weight-%peroxyacetic acid, and about 0.1 to about 5 weight-% peroxyoctanoicacid.

[0012] In one embodiment, an antimicrobial use composition of theinvention includes about 5 to about 1000 ppm acetic acid, about 0.5 toabout 100 ppm octanoic acid, about 1 to about 200 ppm hydrogen peroxide,about 2 to about 300 ppm peroxyacetic acid, and about 0.1 to about 20ppm peroxyoctanoic acid.

[0013] The compositions of the invention and other mixedperoxycarboxylic acid antimicrobial compositions can be employed inmethods for reducing microbial contamination on poultry and in waterused for washing or processing poultry. Preferred mixed peroxycarboxylicacid antimicrobial compositions for use in the methods of the inventioninclude mixtures of peroxyacetic acid and peroxyoctanoic acid in eitherliquid or gaseous form. These methods include applying to the poultryduring processing a mixed peroxycarboxylic acid antimicrobialcomposition, preferably in an amount and time sufficient to reduce themicrobial population. The composition can be applied by methodsincluding submersing, rinsing, spraying, or air chilling the poultry, ora combination of these routes. During processing, the composition can beapplied to whole, dismembered, portioned, or boned poultry.

[0014] In one embodiment of the method of the invention, the methodincludes recovering a mixed peroxycarboxylic acid antimicrobialcomposition previously applied to poultry. The recovered composition canbe treated by adding a sufficient amount of a mixture ofperoxycarboxylic acids to yield a recycled mixed peroxycarboxylic acidantimicrobial composition. The recycled mixed composition includes areduced level of microbes, such as human pathogens, and can be disposedof more safely. Alternatively, the recycled mixed composition can beapplied to poultry during processing. Preferably, the mixture ofperoxycarboxylic acids added to form the recycled composition is formedby adding a concentrate composition of peroxyacetic acid andperoxyoctanoic acid to form a composition with suitable useantimicrobial levels of these peroxycarboxylic acids.

[0015] The compositions can include peroxyheptanoic and/orperoxynonanoic acid in place of or in addition to peroxyoctanoic acid.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Definitions

[0017] As used herein the term “poultry” refers to all forms of any birdkept, harvested, or domesticated for meat or eggs, and includingchicken, turkey, ostrich, game hen, squab, guinea fowl, pheasant, quail,duck, goose, emu, or the like and the eggs of these birds. Poultryincludes whole, sectioned, processed, cooked or raw poultry, andencompasses all forms of poultry flesh, by-products, and side products.The flesh of poultry includes muscle, fat, organs, skin, bones and bodyfluids and like components that form the animal. Forms of animal fleshinclude, for example, the whole or part of animal flesh, alone or incombination with other ingredients. Typical forms include, for example,processed poultry meat, such as cured poultry meat, sectioned and formedproducts, minced products, finely chopped products and whole products.

[0018] As used herein, the terms “mixed” or “mixture” when used relatingto “peroxycarboxylic acid composition” or “peroxycarboxylic acids” referto a composition or mixture including more than one peroxycarboxylicacid, such as a composition or mixture including peroxyacetic acid andperoxyoctanoic acid.

[0019] As used herein, the phrase “poultry debris” refers to any debris,residue, material, dirt, offal, poultry part, poultry waste, poultryviscera, poultry organ, fragments or combinations of such materials, andthe like removed from a poultry carcass or portion during processing andthat enters a waste stream.

[0020] As used herein, the phrase “densified fluid” refers to a fluid ina critical, subcritical, near critical, or supercritical state. Thefluid is generally a gas at standard conditions of one atmospherepressure and 0° C. As used herein, the phrase “supercritical fluid”refers to a dense gas that is maintained above its critical temperature,the temperature above which it cannot be liquefied by pressure.Supercritical fluids are typically less viscous and diffuse more readilythan liquids. Preferably a densified fluid is at, above, or slightlybelow its critical point. As used herein, the phrase “critical point” isthe transition point at which the liquid and gaseous states of asubstance merge into each other and represents the combination of thecritical temperature and critical pressure for a substance. The criticalpressure is a pressure just sufficient to cause the appearance of twophases at the critical temperature. Critical temperatures and pressureshave been reported for numerous organic and inorganic compounds andseveral elements.

[0021] As used herein, the terms “near critical” fluid or “subcritical”fluid refer to a fluid material that is typically below the criticaltemperature of a supercritical fluid, but remains in a fluid state anddenser than a typical gas due to the effects of pressure on the fluid.Preferably a subcritical or near critical fluid is at a temperatureand/or pressure just below its critical point. For example, asubcritical or near critical fluid can be below its critical temperaturebut above its critical pressure, below its critical pressure but aboveits critical temperature, or below both its critical temperature andpressure. The terms near critical and subcritical do not refer tomaterials in their ordinary gaseous or liquid state.

[0022] As used herein, the term “about” modifying the quantity of aningredient in the compositions of the invention or employed in themethods of the invention refers to variation in the numerical quantitythat can occur, for example, through typical measuring and liquidhandling procedures used for making concentrates or use solutions in thereal world; through inadvertent error in these procedures; throughdifferences in the manufacture, source, or purity of the ingredientsemployed to make the compositions or carry out the methods; and thelike. The term about also encompasses amounts that differ due todifferent equilibrium conditions for a composition resulting from aparticular initial mixture. Whether or not modified by the term “about”,the claims include equivalents to the quantities.

[0023] Differentiation of antimicrobial “-cidal” or “-static” activity,the definitions which describe the degree of efficacy, and the officiallaboratory protocols for measuring this efficacy are considerations forunderstanding the relevance of antimicrobial agents and compositions.Antimicrobial compositions can effect two kinds of microbial celldamage. The first is a lethal, irreversible action resulting in completemicrobial cell destruction or incapacitation. The second type of celldamage is reversible, such that if the organism is rendered free of theagent, it can again multiply. The former is termed microbiocidal and thelater, microbistatic. A sanitizer and a disinfectant are, by definition,agents which provide antimicrobial or microbiocidal activity. Incontrast, a preservative is generally described as an inhibitor ormicrobistatic composition.

[0024] For the purpose of this patent application, successful microbialreduction is achieved when the microbial populations are reduced by atleast about 50%, or by significantly more than is achieved by a washwith water. Larger reductions in microbial population provide greaterlevels of protection for processed poultry product.

[0025] As used herein, a composition or combination “consistingessentially” of certain ingredients refers to a composition includingthose ingredients and lacking any ingredient that materially affects thebasic and novel characteristics of the composition or method. The phrase“consisting essentially of” excludes from the claimed compositions andmethods: a coupling agent; an ingredient that cannot be employed in foodproducts or in food wash, handling, or processing according to U.S.government rules or regulations; and/or a peroxycarboxylic acid orcarboxylic acid with 10 or more carbon atoms; unless such an ingredientis specifically listed after the phrase.

[0026] Peroxycarboxylic Acid Antimicrobial Composition

[0027] Compositions of Carboxylic Acids and Peroxycarboxylic Acids

[0028] Among other constituents, the composition of the presentinvention includes a carboxylic acid. Generally, carboxylic acids havethe formula R—COOH wherein the R can represent any number of differentgroups including aliphatic groups, alicyclic groups, aromatic groups,heterocyclic groups, all of which can be saturated or unsaturated aswell as substituted or unsubstituted. Carboxylic acids can have one,two, three, or more carboxyl groups. The composition and methods of theinvention can employ carboxylic acids containing as many as 18 carbonatoms. Examples of suitable carboxylic acids include formic, acetic,propionic, butanoic, pentanoic, hexanoic, heptanoic, octanoic, nonanoic,decanoic, undecanoic, dodecanoic, lactic, maleic, ascorbic, citric,hydroxyacetic, neopentanoic, neoheptanoic, neodecanoic, oxalic, malonic,succinic, glutaric, adipic, pimelic and subric acid. Carboxylic acidswhich are generally useful are those having one or two carboxyl groupswhere the R group is a primary alkyl chain having a length of C₂ to C₁₂.The primary alkyl chain is that carbon chain of the molecule having thegreatest length of carbon atoms and directly appending carboxylfunctional groups. Octanoic acid can reduce surface tension to assist inwetting of hydrophobic surfaces like poultry skin.

[0029] Peroxycarboxylic (or percarboxylic) acids generally have theformula R(CO₃H)_(n), where R is an alkyl, arylalkyl, cycloalkyl,aromatic or heterocyclic group, and n is one, two, or three, and namedby prefixing the parent acid with peroxy. While peroxycarboxylic acidsare not as stable as carboxylic acids, their stability generallyincreases with increasing molecular weight. Thermal decomposition ofthese acids can generally proceed by free radical and nonradical paths,by photodecomposition or radical-induced decomposition, or by the actionof metal ions or complexes. Percarboxylic acids can be made by thedirect, acid catalyzed equilibrium action of hydrogen peroxide with thecarboxylic acid, by autoxidation of aldehydes, or from acid chlorides,and hydrides, or carboxylic anhydrides with hydrogen or sodium peroxide.

[0030] Peroxycarboxylic acids useful in the compositions and methods ofthe present invention include peroxyformic, peroxyacetic,peroxypropionic, peroxybutanoic, peroxypentanoic, peroxyhexanoic,peroxyheptanoic, peroxyoctanoic, peroxynonanoic, peroxydecanoic,peroxyundecanoic, peroxydodecanoic, peroxylactic, peroxymaleic,peroxyascorbic, peroxyhydroxyacetic, peroxyoxalic, peroxymalonic,peroxysuccinic, peroxyglutaric, peroxyadipic, peroxypimelic andperoxysubric acid and mixtures thereof. Peroxy forms of carboxylic acidswith more than one carboxylate moiety can have one or more of thecarboxyl moieties present as peroxycarboxyl moieties. Theseperoxycarboxylic acids have been found to provide good antimicrobialaction with good stability in aqueous mixtures. In a preferredembodiment, the composition of the invention utilizes a combination ofseveral different peroxycarboxylic acids. Preferably, the compositionincludes one or more small C₂-C₄ peroxycarboxylic acids and one or morelarge C₇-C₉ peroxycarboxylic acids. Especially preferred is anembodiment in which the small peroxycarboxylic acid is peroxyacetic acidand the large acid is peroxyoctanoic acid.

[0031] Typically, the compositions and methods of the present inventioninclude peroxyacetic acid. Peroxyacetic (or peracetic) acid is aperoxycarboxylic acid having the formula: CH₃COOOH. Generally,peroxyacetic acid is a liquid having an acrid odor at higherconcentrations and is freely soluble in water, alcohol, ether, andsulfuric acid. Peroxyacetic acid can be prepared through any number ofmethods known to those of skill in the art including preparation fromacetaldehyde and oxygen in the presence of cobalt acetate. A solution ofperoxyacetic acid can be obtained by combining acetic acid with hydrogenperoxide. A 50% solution of peroxyacetic acid can be obtained bycombining acetic anhydride, hydrogen peroxide and sulfuric acid. Othermethods of formulation of peroxyacetic acid include those disclosed inU.S. Pat. No. 2,833,813, which is incorporated herein by reference.

[0032] Typically, the compositions and methods of the present inventioninclude peroxyoctanoic acid, peroxynonanoic acid, or peroxyheptanoicacid, preferably peroxyoctanoic acid. Peroxyoctanoic (or peroctanoic)acid is a peroxycarboxylic acid having the formula, for example, ofn-peroxyoctanoic acid: CH₃(CH₂)₆COOOH. Peroxyoctanoic acid can be anacid with a straight chain alkyl moiety, an acid with a branched alkylmoiety, or a mixture thereof. Peroxyoctanoic acid can be preparedthrough any number of methods known to those of skill in the art. Asolution of peroxyoctanoic acid can be obtained by combining octanoicacid and hydrogen peroxide.

[0033] A preferred antimicrobial composition of the present inventionincludes acetic acid, octanoic acid, peroxyacetic acid, andperoxyoctanoic acid. Such a composition can also include a chelatingagent. A preferred composition preferably includes a combination ofperoxyacetic acid and peroxyoctanoic acid effective for killing one ormore of the food-borne pathogenic bacteria associated with poultry, suchas Salmonella typhimurium, Campylobacter jejuni, Listeria monocytogenes,and Escherichia coli O157:H7, and the like. The compositions and methodsof the present invention have activity against a wide variety ofmicroorganisms such as Gram positive (for example, Listeriamonocytogenes) and Gram negative (for example, Escherichia coli)bacteria, yeast, molds, bacterial spores, viruses, etc. The compositionsand methods of the present invention, as described above, have activityagainst a wide variety of human pathogens. The compositions and methodscan kill a wide variety of microbes on the surface of a poultry or inwater used for washing or processing of poultry.

[0034] The preferred compositions include concentrate compositions anduse compositions. Typically, an antimicrobial concentrate compositioncan be diluted, for example with water, to form an antimicrobial usecomposition. In a preferred embodiment, the concentrate composition isdiluted into water employed for washing or processing poultry.

[0035] Liquid Peroxycarboxylic Acid Antimicrobial Composition

[0036] A preferred antimicrobial concentrate composition of the presentinvention includes about 40 to about 70 weight-%, preferably about 45 toabout 65 weight-%, preferably about 50 to about 60 weight-% acetic acid;about 2 to about 20 weight-%, preferably about 2 to about 8 weight-%octanoic acid; and about 5 to about 15 weight-% hydrogen peroxide. Thiscomposition can advantageously also include about 0.3 to about 1weight-% chelating agent. Preferably, such an antimicrobial concentratecomposition includes about 55 weight-% acetic acid, about 11 weight-%hydrogen peroxide, and about 4 weight-% octanoic acid. This compositioncan advantageously also include about 0.6 weight-% chelating agent. Thisconcentrate composition can be prepared according to the proportionsdescribed above. After combining the ingredients in these proportions,certain ingredients, such as the acetic acid, octanoic acid, andhydrogen peroxide, react to form peroxyacetic acid and peroxyoctanoicacid.

[0037] By about two weeks after combining, the reaction of theseingredients has approached equilibrium. That is, the relative amounts ofone or more of peroxyacetic acid, acetic acid, peroxyoctanoic acid,octanoic acid, and hydrogen peroxide will be roughly constant. Theequilibrium amount will be affected by decomposition or other reaction,if any, of any labile species. A preferred antimicrobial concentratecomposition of the present invention includes an equilibrium mixtureresulting from a combination of about 40 to about 70 weight-%,preferably about 45 to about 65 weight-%, preferably about 50 to about60 weight-% acetic acid; about 2 to about 20 weight-%, preferably about2 to about 8 weight-% octanoic acid; and about 5 to about 15 weight-%hydrogen peroxide. This equilibrium composition can advantageously alsoinclude about 0.3 to about 1 weight-% chelating agent. A more preferredantimicrobial concentrate composition of the present invention includesan equilibrium mixture resulting from a combination of about 55 weight-%acetic acid, about 11 weight-% hydrogen peroxide, and about 4 weight-%octanoic acid. This equilibrium composition can advantageously alsoinclude about 0.6 weight-% chelating agent.

[0038] A preferred antimicrobial concentrate composition of the presentinvention includes about 30 to about 60 weight-%, preferably about 35 toabout 60 weight-%, preferably about 35 to about 50 weight-%, preferablyabout 40 to about 50 weight-% acetic acid; about 1 to about 15 weight-%,preferably about 1 to about 7 weight-% octanoic acid; about 2 to about12 weight-%, preferably about 2 to about 8 weight-% hydrogen peroxide;about 6 to about 16 weight-%, preferably about 8 to about 16 weight-%peroxyacetic acid; and about 0.1 to about 5 weight-%, preferably about0.1 to about 2 weight-% peroxyoctanoic acid. This concentratecomposition can advantageously also include about 0.1 to about 2weight-% chelating agent. Preferably, such an antimicrobial concentratecomposition includes about 40 weight-% acetic acid, about 3 weight-%octanoic acid, about 6 weight-% hydrogen peroxide, about 10 weight-%peroxyacetic acid, and about 0.8 weight-% peroxyoctanoic acid. Thisantimicrobial concentrate composition can advantageously include about0.6 weight-% chelating agent. Preferably, such an antimicrobialconcentrate composition includes about 41 weight-% acetic acid, about3.2 weight-% octanoic acid, about 6.2 weight-% hydrogen peroxide, about12 weight-% peroxyacetic acid, and about 0.80 weight-% peroxyoctanoicacid. This antimicrobial concentrate composition can advantageouslyinclude about 0.60 weight-% chelating agent. These preferredcompositions can be produced by mixing the acid and peroxide componentsat proportions listed in preceding paragraphs and allowing thecomposition to sit at ambient temperature for a period of about one toabout two weeks. That is, these preferred compositions can be consideredequilibrium compositions.

[0039] The compositions of the present invention also includeantimicrobial use compositions. Preferred antimicrobial use compositionsinclude about 5 to about 1000 ppm acetic acid; about 0.5 to about 100ppm, preferably about 0.5 to about 75 ppm octanoic acid; about 1 toabout 200 ppm, preferably about 1 to about 110 ppm hydrogen peroxide;about 2 to about 300 ppm, preferably about 2 to about 220 ppmperoxyacetic acid, and about 0.1 to about 20 ppm peroxyoctanoic acid.Such a use composition can advantageously include about 0.05 to about 30ppm chelating agent. Preferably, such an antimicrobial use compositionincludes about 7 (e.g., 6.8) ppm acetic acid, about 0.5 ppm octanoicacid, about 1 ppm hydrogen peroxide, about 2 ppm peroxyacetic acid, andabout 0.1 ppm peroxyoctanoic acid. This use composition canadvantageously include about 0.1 ppm chelating agent. Preferably, suchan antimicrobial use composition includes about 20 (e.g. 17) ppm aceticacid, about 1 to about 2 (e.g., 1.3) ppm octanoic acid, about 2 to about3 (e.g., 2.6) ppm hydrogen peroxide, about 5 ppm peroxyacetic acid, andabout 0.3 ppm peroxyoctanoic acid. This use composition canadvantageously include about 0.3 ppm chelating agent. Preferably, suchan antimicrobial use composition includes about 100 (e.g., 101) ppmacetic acid, about 8 ppm octanoic acid, about 10 to about 20 (e.g., 16)ppm hydrogen peroxide, about 30 ppm peroxyacetic acid, and about 2 ppmperoxyoctanoic acid. This use composition can advantageously includeabout 1 to about 2 (e.g. 1.5) ppm chelating agent. Preferably, such anantimicrobial use composition includes about 1000 (e.g. 985) ppm aceticacid, about 70 to about 80 (e.g. 74) ppm octanoic acid, about 100 toabout 200 (e.g. 110) ppm hydrogen peroxide, about 220 (e.g., 213) ppmperoxyacetic acid, and about 10 to about 20 (e.g. 14) ppm peroxyoctanoicacid. This use composition can advantageously include about 10 to about20 (e.g., 13) ppm chelating agent. Different dilutions of a concentratecomposition can result in different levels of the components of the usecomposition, generally maintaining the relative proportions. Forexample, a use composition of the present invention can haveconcentrations twice, one half, or one quarter those listed above.

[0040] More About Liquid Peroxycarboxylic Acid Compositions

[0041] The level of reactive species, such as peroxy acids and/orhydrogen peroxide, in a use composition can be affected, typicallydiminished, by organic matter that is found in or added to the usecomposition. For example, when the use composition is a bath or sprayused for washing poultry, poultry organic matter or accompanying organicmatter will consume peroxy acid and peroxide. Thus, the present amountsof ingredients in the use compositions refer to the composition beforeor early in use, with the understanding that the amounts will diminishas organic matter is added to the use composition.

[0042] In addition, the concentrate and use compositions change withage. It is believed that in approximately one year at ambient conditionsthe amount of peroxycarboxylic acid in the compositions can decrease toabout 70% to about 80%, preferably about 80% to about 85%, of theinitial equilibrium values or use composition levels. Such agedcompositions are included in the scope of the present invention.

[0043] In each of the compositions described above, the chelating agentis an optional, but preferred, ingredient. Typically the balance of eachof the compositions described above is made up primarily or exclusivelyof a solvent, such as water, e.g. tap or other potable water.

[0044] The compositions of the present invention preferably include onlyingredients that can be employed in poultry products or in poultry wash,handling, or processing, for example, according to government (e.g. FDAor USDA) rules and regulations. Preferably, the composition is free ofany peroxycarboxylic acid or carboxylic acid with 10, 12, or more carbonatoms. Such 10, 12, or more carbon acids can impart undesirable residues(e.g. bad tasting and/or malodorous) to poultry.

[0045] Each of the compositions listed above can be formulated bycombining each of the listed ingredients. In addition, certaincompositions including both acid and peroxy acid can be formulated bycombining the acids and hydrogen peroxide, which forms peroxy acids.Typically, the pH of an equilibrium mixture is less than about 1 orabout 2, and the pH of a 1% solution of the equilibrium mixture in wateris about 2 to about 7, depending on the other components of the 1%solution, and the pH of a use composition can be from about 4 to about 7depending on the other components.

[0046] Other Fluid Compositions

[0047] The present methods can employ antimicrobial compositionsincluding a critical, near critical, or supercritical (densified) fluidand an antimicrobial agent or a gaseous composition of an antimicrobialagent. The densified fluid can be a near critical, critical,supercritical fluid, or another type of fluid with properties of asupercritical fluid. Fluids suitable for densification include carbondioxide, nitrous oxide, ammonia, xenon, krypton, methane, ethane,ethylene, propane, certain fluoroalkanes (e.g., chlorotrifluoromethaneand monofluoromethane), and the like, or mixtures thereof. Preferredfluids include carbon dioxide. The antimicrobial composition can alsoinclude other ingredients, such as another fluid or gas; a carrier,solvent or cosolvent; an oxidizing agent; a fatty acid; or a mixturethereof.

[0048] The antimicrobial agent applied with a densified fluid system canbe any of a variety of food surface compatible antimicrobial agents,such as one or more peroxycarboxylic acids, quaternary ammoniumantimicrobial agents, acid sanitizers, mixtures thereof, and other foodsurface compatible antimicrobial agents. A preferred densified fluidantimicrobial composition that can be employed in the present methodsincludes densified carbon dioxide, peroxyacetic acid, hydrogen peroxide,acetic acid, peroxyoctanoic acid, and octanoic acid, which can bereferred to as a densified fluid mixed peroxycarboxylic acidcomposition.

[0049] In another embodiment, the antimicrobial composition includes thefluid, an antimicrobial agent, and any of the optional or addedingredients, but is in the form of a gas.

[0050] Densified fluid antimicrobial compositions can be applied by anyof several methods known to those of skill in the art. Such methodsinclude venting at the poultry carcass or part a vessel containingdensified fluid and antimicrobial agent. The aqueous phase, whichincludes hydrogen peroxide, is advantageously retained in the device.The vented gas includes an effective amount of antimicrobial agentmaking the densified fluid peroxycarboxylic acid compositions effectiveantimicrobial agents.

[0051] Because of the high pressure nature of the densified fluidcompositions of the invention, these compositions are typically appliedby venting a vessel containing the composition through a pressure reliefdevice that is designed to promote rapid efficient coverage of thepoultry carcass or part. Devices including such a pressure relief deviceinclude sprayers, foggers, foamers, foam pad applicators, brushapplicators or any other device that can permit the expansion of thefluid materials from high pressure to ambient pressure while applyingthe material to the poultry carcass or part.

[0052] The densified fluid peroxycarboxylic acid composition can also beapplied to poultry by any of a variety of methods known for applyinggaseous agents to poultry during processing, including air chilling andpackaging (e.g. modified atmosphere packaging), particularly at stepswhere adding water to the poultry is disadvantageous. Other points inpoultry processing suitable for application of a gaseousperoxycarboxylic acid composition include any step including inertatmosphere processing, carbon dioxide stunning, and the like.

[0053] Densified fluid antimicrobial compositions can be made byreacting an oxidizable substrate with an oxidizing agent in a mediumcomprising a densified fluid to form an antimicrobial composition. Thisreaction is typically carried out in a vessel suitable for containing adensified fluid. Reacting can include adding to the vessel theoxidizable substrate and the oxidizing agent, and adding fluid to thevessel to form the densified fluid. A preferred reaction system involvesa reaction between a carboxylic acid and hydrogen peroxide to form thecorresponding peroxycarboxylic acid. The hydrogen peroxide is commonlysupplied in the form of an aqueous solution of hydrogen peroxide.Preferred carboxylic acids include acetic acid, heptanoic acid, octanoicacid, nonanoic acid, and mixtures thereof.

[0054] Supercritical, subcritical, near supercritical, and other densefluids and solvents that can be employed with such fluids are disclosedin U.S. Pat. No. 5,306,350, issued Apr. 26, 1994 to Hoy et al., which isincorporated herein for such disclosure. Supercritical and other denseforms of carbon dioxide, and cosolvents, co-surfactants, and otheradditives that can be employed with these forms of carbon dioxide aredisclosed in U.S. Pat. No. 5,866,005, issued Feb. 2, 1999 to DeSimone etal., which is incorporated herein for such disclosure.

[0055] Hydrogen Peroxide

[0056] The antimicrobial composition of the invention typically alsoinclude a hydrogen peroxide constituent. Hydrogen peroxide incombination with the percarboxylic acid provides certain antimicrobialaction against microorganisms. Additionally, hydrogen peroxide canprovide an effervescent action which can irrigate any surface to whichit is applied. Hydrogen peroxide works with a mechanical flushing actiononce applied which further cleans the surface of application. Anadditional advantage of hydrogen peroxide is the food compatibility ofthis composition upon use and decomposition. For example, combinationsof peroxyacetic acid, peroxyoctanoic acid, and hydrogen peroxide resultin acetic acid, octanoic acid, water, and oxygen upon decomposition, allof which are food product compatible.

[0057] Many oxidizing agents can be used for generating peroxycarboxylicacids. Suitable oxidizing agents, in addition to hydrogen peroxide,include perborate, percarbonate, and persulfate. Hydrogen peroxide isgenerally preferred for several reasons. After application of theH₂O₂/peroxycarboxylic acid germicidal agent, the residue left merelyincludes water and an acidic constituent. Deposition of these productson the surface of a poultry processing apparatus, such as a bath orspray apparatus, will not adversely effect the apparatus, the handlingor processing, or the poultry washed therein.

[0058] Hydrogen peroxide (H₂O₂), has a molecular weight of 34.014 and itis a weakly acidic, clear, colorless liquid. The four atoms arecovalently bonded in a H—O—O—H structure. Generally, hydrogen peroxidehas a melting point of −0.41° C., a boiling point of 150.2° C., adensity at 25° C. of 1.4425 grams per cm³, and a viscosity of 1.245centipoise at 20° C.

[0059] Carrier

[0060] The composition of the invention also includes a carrier. Thecarrier provides a medium which dissolves, suspends, or carries theother components of the composition. For example, the carrier canprovide a medium for solubilization and production of peroxycarboxylicacid and for forming an equilibrium mixture. The carrier also functionsto deliver and wet the antimicrobial composition of the invention to thepoultry. To this end, the carrier may contain any component orcomponents that can facilitate these functions.

[0061] Generally, the carrier includes primarily water which is anexcellent solubilizer and medium for reaction and equilibrium. Thecarrier can include or be primarily an organic solvent, such as simplealkyl alcohols, e.g., ethanol, isopropanol, n-propanol, and the like.Polyols are also useful carriers, including propylene glycol,polyethyleneglycol, glycerol, sorbitol, and the like. Any of thesecompounds may be used singly or in combination with other organic orinorganic constituents or, in combination with water or in mixturesthereof.

[0062] Generally, the carrier makes up a large portion of thecomposition of the invention and may be the balance of the compositionapart from the active antimicrobial components, adjuvants, and the like.Here again, the carrier concentration and type will depend upon thenature of the composition as a whole, the environmental storage, andmethod of application including concentration of the antimicrobialagent, among other factors. Notably the carrier should be chosen andused at a concentration which does not inhibit the antimicrobialefficacy of the active agent in the composition of the invention.

[0063] Adjuvants

[0064] The antimicrobial composition of the invention can also includeany number of adjuvants. Specifically, the composition of the inventioncan include stabilizing agents, wetting agents, hydrotropes, thickeners,a surfactant, foaming agents, acidifiers, as well as pigments or dyesamong any number of constituents which can be added to the composition.Such adjuvants can be preformulated with the antimicrobial compositionof the invention or added to the system simultaneously, or even after,the addition of the antimicrobial composition. The composition of theinvention can also contain any number of other constituents asnecessitated by the application, which are known to those of skill inthe art and which can facilitate the activity of the present invention.

[0065] Stabilizing Agents

[0066] Stabilizing agents can be added to the composition of theinvention, for example, to stabilize the peracid and hydrogen peroxideand prevent the premature oxidation of this constituent within thecomposition of the invention.

[0067] Chelating agents or sequestrants generally useful as stabilizingagents in the present compositions include alkyl diamine polyaceticacid-type chelating agents such as EDTA (ethylene diamine tetraacetatetetrasodium salt), acrylic and polyacrylic acid-type stabilizing agents,phosphonic acid, and phosphonate-type chelating agents among others.Preferable sequestrants include phosphonic acids and phosphonate saltsincluding 1-hydroxy ethyldene -1,1-diphosphonic acid (CH₃C(PO₃H₂)₂OH)(HEDP), amino[tri(methylene phosphonic acid)] ([CH₂PO₃H₂]₂(ethylenediamine[tetra methylene-phosphonic acid)], 2-phosphenebutane-1,2,4-tricarboxylic acid, as well as the alkyl metal salts,ammonium salts, or alkyloyl amine salts, such as mono, di, ortetra-ethanolamine salts. The stabilizing agent is used in aconcentration ranging from about 0 weight percent to about 20 weightpercent of the composition, preferably from about 0.1 weight percent toabout 10 weight percent of the composition, and most preferably fromabout 0.2 weight percent to 5 weight percent of the composition.

[0068] Amino phosphates and phosphonates are also suitable for use aschelating agents in the compositions of the invention and includeethylene diamine (tetramethylene phosphonates), nitrilotrismethylenephosphates, diethylenetriamine (pentamethylene phosphonates). Theseamino phosphonates commonly contain alkyl or alkaline groups with lessthan 8 carbon atoms. The phosphonic acid may also include a lowmolecular weight phosphonopolycarboxylic acid such as one having about2-4 carboxylic acid moieties and about 1-3 phosphonic acid groups. Suchacids include 1-phosphono-1-methylsuccinic acid, phosphonosuccinic acidand 2-phosphonobutane-1,2,4-tricarboxylic acid.

[0069] Commercially available food additive chelating agents includephosphonates sold under the trade name DEQUEST® including, for example,1-hydroxyethylidene-1,1-diphosphonic acid, available from MonsantoIndustrial Chemicals Co., St. Louis, Mo., as DEQUEST®2010;amino(tri(methylenephosphonic acid)), (N[CH₂PO₃H₂]₃), available fromMonsanto as DEQUEST® 2000; ethylenediamine[tetra(methylenephosphonicacid)] available from Monsanto as DEQUEST® 2041; and2-phosphonobutane-1,2,4-tricarboxylic acid available from Mobay ChemicalCorporation, Inorganic Chemicals Division, Pittsburgh, Pa., as BayhibitAM.

[0070] The above-mentioned phosphonic acids can also be used in the formof water soluble acid salts, particularly the alkali metal salts, suchas sodium or potassium; the ammonium salts or the alkylol amine saltswhere the alkylol has 2 to 3 carbon atoms, such as mono-, di-, ortriethanolamine salts. If desired, mixtures of the individual phosphonicacids or their acid salts can also be used.

[0071] The concentration of chelating agent useful in the presentinvention generally ranges from about 0.01 to about 10 wt-%, preferablyfrom about 0.1 to about 5 wt-%, most preferably from about 0.5 to about2 wt-%.

[0072] Wetting or Defoaming Agents

[0073] Also useful in the composition of the invention are wetting anddefoaming agents. Wetting agents function to increase the surfacecontact or penetration activity of the antimicrobial composition of theinvention. Wetting agents which can be used in the composition of theinvention include any of those constituents known within the art toraise the surface activity of the composition of the invention.

[0074] Along these lines, surfactants, and especially nonionicsurfactants, can also be useful in the present invention. Nonionicsurfactants which can be useful in the present invention are those whichinclude ethylene oxide moieties, propylene oxide moieties, as well amixtures thereof, and ethylene oxide-propylene oxide moieties in eitherheteric or block formation. Additionally useful in the present inventionare nonionic surfactants which include an alkyl ethylene oxidecompounds, alkyl propylene oxide compounds, as well as mixtures thereof,and alkyl ethylene oxide-propylene oxide compounds where the ethyleneoxide propylene oxide moiety is either in heteric or block formation.Further useful in the present invention are nonionic surfactants havingany mixture or combination of ethylene oxide-propylene oxide moietieslinked to a alkyl chain where the ethylene oxide and propylene oxidemoieties can be in any randomized or ordered pattern and of any specificlength. Nonionic surfactants useful in the present invention can alsoinclude randomized sections of block and heteric ethylene oxidepropylene oxide, or ethylene oxide-propylene oxide, such as ethylenediamine ethylene oxides, ethylene diamine propylene oxides, mixturesthereof, and ethylene diamine EO-PO compounds, including those soldunder the tradename Tetronic.

[0075] Generally, the concentration of nonionic surfactant used in acomposition of the present invention can range from about 0 wt-% toabout 5 wt-% of the composition, preferably from about 0 wt-% to about 2wt-% of the concentrate composition, and most preferably from about 0wt-% to about 1 wt-% of the composition.

[0076] The composition used in the methods of the invention can alsocontain additional ingredients as necessary to assist in defoaming.

[0077] Generally, defoamers which can be used in accordance with theinvention include silica and silicones; aliphatic acids or esters;alcohols; sulfates or sulfonates; amines or amides; halogenatedcompounds such as fluorochlorohydrocarbons; vegetable oils, waxes,mineral oils as well as their sulfated derivatives; fatty acid soapssuch as alkali, alkaline earth metal soaps; and phosphates and phosphateesters such as alkyl and alkaline diphosphates, and tributyl phosphatesamong others; and mixtures thereof.

[0078] Especially preferable, are those antifoaming agents or defoamerswhich are of food grade quality given the application of the method ofthe invention. To this end, one of the more effective antifoaming agentsincludes silicones. Silicones such as dimethyl silicone, glycolpolysiloxane, methylphenol polysiloxane, trialkyl or tetralkyl silanes,hydrophobic silica defoamers and mixtures thereof can all be used indefoaming applications. Commercial defoamers commonly available includesilicones such as Ardefoam® from Armour Industrial Chemical Companywhich is a silicone bound in an organic emulsion; Foam Kill® or Kresseo®available from Krusable Chemical Company which are silicone andnon-silicone type defoamers as well as silicone esters; and Anti-Foam A®and DC-200 from Dow Corning Corporation which are both food grade typesilicones among others. These defoamers can be present at aconcentration range from about 0.01 wt-% to 5 wt-%, preferably fromabout 0.01 wt-% to 2 wt-%, and most preferably from about 0.01 wt-% toabout 1 wt-%.

[0079] Hydrotrope

[0080] The poultry wash composition of the invention or employed in themethods of the invention may also include a hydrotrope coupler orsolubilizer. Such materials can be used to ensure that the compositionremains phase stable and in a single highly active aqueous form. Suchhydrotrope solubilizers or couplers can be used at compositions whichmaintain phase stability but do not result in unwanted compositionalinteraction.

[0081] Representative classes of hydrotrope solubilizers or couplingagents include an anionic surfactant such as an alkyl sulfate, an alkylor alkane sulfonate, a linear alkyl benzene or naphthalene sulfonate, asecondary alkane sulfonate, alkyl ether sulfate or sulfonate, an alkylphosphate or phosphonate, dialkyl sulfosuccinic acid ester, sugar esters(e.g., sorbitan esters) and a C₈₋₁₀ alkyl glucoside.

[0082] Preferred coupling agents for use in the rinse agents of theinvention include n-octane sulfonate and aromatic sulfonates such as analkyl aryl sulfonate (e.g., sodium xylene sulfonate or naphthalenesulfonate). Many hydrotrope solubilizers independently exhibit somedegree of antimicrobial activity at low pH. Such action adds to theefficacy of the invention but is not a primary criterion used inselecting an appropriate solubilizing agent. Since the presence of theperoxycarboxylic acid material in the protonated neutral state providesbeneficial biocidal or antimicrobial activity, the coupling agent shouldbe selected not for its independent antimicrobial activity but for itsability to provide effective single phase composition stability in thepresence of substantially insoluble peroxycarboxylic acid materials andthe more soluble compositions of the invention. Generally, any number ofsurfactants may be used consistent with the purpose of this constituent.

[0083] Anionic surfactants useful with the invention include alkylcarboxylates, linear alkylbenzene sulfonates, paraffin sulfonates andsecondary n-alkane sulfonates, sulfosuccinate esters and sulfated linearalcohols.

[0084] Zwitterionic or amphoteric surfactants useful with the inventioninclude β-N-alkylaminopropionic acids, n-alkyl-β-iminodipropionic acids,imidazoline carboxylates, n-alky-Iletaines, amine oxides, sulfobetainesand sultaines.

[0085] Nonionic surfactants useful in the context of this invention aregenerally polyether (also known as polyalkylene oxide, polyoxyalkyleneor polyalkylene glycol) compounds. More particularly, the polyethercompounds are generally polyoxypropylene or polyoxyethylene glycolcompounds. Typically, the surfactants useful in the context of thisinvention are synthetic organic polyoxypropylene (PO)-polyoxyethylene(EO) block copolymers. These surfactants have a diblock polymerincluding an EO block and a PO block, a center block of polyoxypropyleneunits (PO), and having blocks of polyoxyethylene grated onto thepolyoxypropylene unit or a center block of EO with attached PO blocks.Further, this surfactant can have further blocks of eitherpolyoxyethylene or polyoxypropylene in the molecule. The averagemolecular weight of useful surfactants ranges from about 1000 to about40,000 and the weight percent content of ethylene oxide ranges fromabout 10-80% by weight.

[0086] Also useful in the context of this invention are surfactantsincluding alcohol alkoxylates having EO, PO and BO blocks. Straightchain primary aliphatic alcohol alkoxylates can be particularly usefulas sheeting agents. Such alkoxylates are also available from severalsources including BASF Wyandotte where they are known as “Plurafac”surfactants. A particular group of alcohol alkoxylates found to beuseful are those having the general formula R-(EO)_(m)—(PO)_(n) whereinm is an integer of about 2-10 and n is an integer from about 2-20. R canbe any suitable radical such as a straight chain alkyl group having fromabout 6-20 carbon atoms.

[0087] Other useful nonionic surfactants of the invention include cappedaliphatic alcohol alkoxylates. These end caps include but are notlimited to methyl, ethyl, propyl, butyl, benzyl and chlorine. Usefulalcohol alkoxylated include ethylene diamine ethylene oxides, ethylenediamine propylene oxides, mixtures thereof, and ethylene diamine EO-POcompounds, including those sold under the tradename Tetronic.Preferably, such surfactants have a molecular weight of about 400 to10,000. Capping improves the compatibility between the nonionic and theoxidizers hydrogen peroxide and peroxycarboxylic acid, when formulatedinto a single composition. Other useful nonionic surfactants arealkylpolyglycosides.

[0088] Another useful nonionic surfactant of the invention is a fattyacid alkoxylate wherein the surfactant includes a fatty acid moiety withan ester group including a block of EO, a block of PO or a mixed blockor heteric group. The molecular weights of such surfactants range fromabout 400 to about 10,000, a preferred surfactant has an EO content ofabout 30 to 50 wt-% and wherein the fatty acid moiety contains fromabout 8 to about 18 carbon atoms.

[0089] Similarly, alkyl phenol alkoxylates have also been found usefulin the invention. Such surfactants can be made from an alkyl phenolmoiety having an alkyl group with 4 to about 18 carbon atoms, cancontain an ethylene oxide block, a propylene oxide block or a mixedethylene oxide, propylene oxide block or heteric polymer moiety.Preferably such surfactants have a molecular weight of about 400 toabout 10,000 and have from about 5 to about 20 units of ethylene oxide,propylene oxide or mixtures thereof.

[0090] The concentration of hydrotrope useful in the present inventiongenerally ranges from about 0.1 to about 20 wt-%, preferably from about0.5 to about 10 wt-%, most preferably from about 1 to about 4 wt-%.

[0091] Thickening or Gelling Agents

[0092] Thickeners useful in the present invention include those which donot leave contaminating residue on the surface of poultry or poultryprocessing apparatus. That is, preferred thickeners or gelling agents donot include components incompatible with food or other sensitiveproducts in contact areas.

[0093] Generally, thickeners which may be used in the present inventioninclude natural gums such as xanthan gum, guar gum, or other gums fromplant mucilage; polysaccharide based thickeners, such as alginates,starches, and cellulosic polymers (e.g., carboxymethyl cellulose);polyacrylates thickeners; and hydrocolloid thickeners, such as pectin.Generally, the concentration of thickener employed in the presentcompositions or methods will be dictated by the desired viscosity withinthe final composition. However, as a general guideline, the viscosity ofthickener within the present composition ranges from about 0.1 wt-% toabout 1.5 wt-%, preferably from about 0.1 wt-% to about 1.0 wt-%, andmost preferably from about 0.1 wt-% to about 0.5 wt-%.

[0094] Formulation

[0095] The compositions of or used in the methods of the invention canbe formulated by combining the antimicrobially active materials (e.g.,carboxylic acids, peroxycarboxylic acids, and hydrogen peroxide) withadjuvant or other components with the materials that form theantimicrobial composition. The compositions can also be formulated withpreformed peroxycarboxylic acids. The preferred compositions of theinvention can be made by mixing the carboxylic acid or mixture thereofwith an optional hydrotrope solubilizer or coupler, reacting the mixturewith hydrogen peroxide and then adding the balance of requiredingredients to provide rinsing and antimicrobial action.

[0096] A stable equilibrium mixture is produced containing thecarboxylic acid or blend with hydrogen peroxide and allowing the mixtureto stand for 1-14 days at 15° C. or more. With this preparatory method,an equilibrium mixture will be formed containing an amount of hydrogenperoxide, unoxidized acid, oxidized or peroxycarboxylic acid andunmodified couplers, solubilizer, or stabilizers.

[0097] Use Compositions

[0098] The invention contemplates a concentrate composition which isdiluted to a use solution prior to application to poultry. Primarily forreasons of economics, the concentrate would normally be marketed and anend user would preferably dilute the concentrate with water or anaqueous diluent to a use solution.

[0099] The level of active components in the concentrate composition isdependent on the intended dilution factor and the desired activity ofthe peroxycarboxylic acid compound and the carboxylic acid. Generally, adilution of about 0.5 to about 20 fluid ounces to about 100 gallons ofwater is used for aqueous antimicrobial compositions. Higher usedilutions can be employed if elevated use temperature (greater than 25°C.) or extended exposure time (greater than 30 seconds) can be employed.In the typical use locus, the concentrate is diluted with a majorproportion of water and used for poultry processing using commonlyavailable tap or service water mixing the materials at a dilution ratioof about 3 to about 20 ounces of concentrate per 100 gallons of water.

[0100] Methods Employing Mixed Peroxycarboxylic Acid Compositions

[0101] Poultry Processing

[0102] The concentrate and use compositions of the present invention canbe employed for a variety of antimicrobial purposes, preferably as orfor forming water-based systems for processing and/or washing poultry.The present compositions and methods can be employed for processingpoultry and/or poultry meat at any step from gathering the live birdsthrough packaging the final product. For example, the presentcompositions and methods can employed for washing, rinsing, chilling, orscalding poultry carcasses, poultry carcass parts, or poultry organs forreducing contamination of these items with spoilage/decay-causingbacteria, and pathogenic bacteria.

[0103] Before processing, live poultry are generally transported to andgathered at the beginning of a processing line. Poultry can be washedbefore entering the processing line. Processing typically begins withsacrificing the bird, typically by electrical stunning, followed by neckcutting and bleeding. A first washing step, known as scalding (e.g.submersion or immersion scalding) typically follows bleeding and loosensattachment of feathers to poultry skin. Submersion scalding can beaccomplished according to the methods and employing compositions of thepresent invention. Submersion scalding typically includes immersing astunned and bled bird into a scalding hot bath of water or a liquidantimicrobial composition, typically at a temperature of about 50 toabout 80° C., preferably about 50 to about 60° C. The liquidantimicrobial composition in the bath can be agitated, sonicated, orpumped to increase contact of the composition with the carcass. Scaldingis generally conducted in a scald tank or trough, which contains thescalding liquid with sufficient liquid depth to completely submerse thepoultry carcass. The carcass is generally transported through the tankor trough by conveyor at a speed that provides a few minutes in thescalding liquid.

[0104] According to the present invention, the scalding bath can includea mixed peroxycarboxylic acid antimicrobial composition, preferably acomposition of the present invention. Preferably, the scalding hot bathcontains a peroxycarboxylic acid antimicrobial composition with about 2to about 50 ppm, preferably about 30 ppm of peroxycarboxylic acidpresent as a mixture of peroxyacetic acid and peroxyoctanoic acid, andamounts and additional ingredients as described herein. The scaldingbath can also include one or more of the additional ingredientspermitted in scalding baths.

[0105] After submersion scalding, the poultry is typically picked and,optionally, singed before the next washing process. This second washingprocess is generally known as “dress” rinsing, “New York dress” rinsing,or post-pick rinsing, which rinses residual feathers and follicleresidues from the carcass. Dress rinsing typically includes spraying apicked carcass with water, typically at a temperature of about 5 toabout 30° C. To increase contact with the carcass, the antimicrobialcompositions in the spray water can be applied at higher pressures, flowrates, temperatures, or with agitation or ultrasonic energy. Dressrinsing is typically accomplished with a washing apparatus such as awash or spray cabinet with stationary or moving spray nozzles.Alternatively, a “flood”-rinsing or liquid submersion washing apparatusmay be used immediately after picking.

[0106] According to the present invention, dress rinsing can beaccomplished employing a peroxycarboxylic acid antimicrobialcomposition, preferably a composition of the present invention. Forexample, the dress rinsing can employ a peroxycarboxylic acidantimicrobial composition with about 50 to about 300 ppm, preferablyabout 200 ppm of peroxycarboxylic acid present as a mixture ofperoxyacetic acid and peroxyoctanoic acid, and amounts and additionalingredients as described herein.

[0107] Dress rinsing is typically a final washing step beforedismembering the poultry. Dismembering can include removing the head,the feet, eviscerating, and removing the neck, in any order commonlyemployed in poultry processing. The dismembered and eviscerated poultrycan then be subjected to a washing step known as inside-outside birdwashing (IOBW). Inside-outside bird washing washes the interior (bodycavity) and exterior of the bird. Inside-outside bird washing typicallyincludes rinsing the interior and exterior surfaces of the carcass withstreams or floods of water, typically at a temperature of about 5 toabout 30° C. To increase contact with the carcass, the antimicrobialcompositions in the spray water can be applied at higher pressures, flowrates, temperatures, or with agitation or ultrasonic energy.Inside-outside bird washing is generally accomplished by an apparatusthat floods the bird carcass with streams of water in the inner cavityand over the exterior of the carcass. Such an apparatus can include aseries of fixed spray nozzles to apply antimicrobial composition to theexterior of the bird and a rinse probe or bayonet that enters andapplies antimicrobial composition to the body cavity.

[0108] According to the present invention, inside-outside bird washingcan be accomplished employing a peroxycarboxylic acid antimicrobialcomposition, preferably a composition of the present invention. Forexample, inside-outside bird washing can employ a peroxycarboxylic acidantimicrobial composition about 20 to about 200 ppm preferably about 50to about 100 ppm of peroxycarboxylic acid present as a mixture ofperoxyacetic acid and peroxyoctanoic acid, and amounts and additionalingredients as described herein.

[0109] After inside-outside bird washing, both the interior and theexterior of the bird can be subjected to further decontamination. Thisfurther decontamination can be accomplished in part by a step commonlyknown as antimicrobial spray rinsing, sanitizing rinsing, or finishingrinsing. Such rinsing typically includes spraying the interior andexterior surfaces of the carcass with water, typically at a temperatureof about 5 to about 30° C. To increase contact with the carcass, theantimicrobial compositions in the spray water can be applied using fixedor articulating nozzles, at higher pressures, flow rates, temperatures,with agitation or ultrasonic energy, or with rotary brushes. Sprayrinsing is typically accomplished by an apparatus such as a spraycabinet with stationary or moving spray nozzles. The nozzles create amist, vapor, or spray that contacts the carcass surfaces.

[0110] According to the present invention, antimicrobial spray rinsing,sanitizing rinsing, or finishing rinsing can be accomplished employing aperoxycarboxylic acid antimicrobial composition, preferably acomposition of the present invention. For example, spray rinsing canemploy a peroxycarboxylic acid antimicrobial composition with about 50to about 300 ppm preferably about 100 to about 200 ppm ofperoxycarboxylic acid present as a mixture of peroxyacetic acid andperoxyoctanoic acid, and amounts and additional ingredients as describedherein.

[0111] After spray rinsing, the bird can be made ready for packaging orfor further processing by chilling, specifically submersion chilling orair chilling. Submersion chilling both washes and cools the bird toretain quality of the meat. Submersion chilling typically includessubmersing the carcass completely in water or slush, typically at atemperature of less than about 5° C., until the temperature of thecarcass approaches that of the water or slush. Chilling of the carcasscan be accomplished by submersion in a single bath, or in two or morestages, each of a lower temperature. Water can be applied with agitationor ultrasonic energy to increase contact with the carcass. Submersionchilling is typically accomplished by an apparatus such as a tankcontaining the chilling liquid with sufficient liquid depth tocompletely submerse the poultry carcass. The carcass can be conveyedthrough the chiller by various mechanisms, such as an auger feed or adrag bottom conveyor. Submersion chilling can also be accomplished bytumbling the carcass in a chilled water cascade.

[0112] According to the present invention, submersion chilling can beaccomplished employing a peroxycarboxylic acid antimicrobialcomposition, preferably a composition of the present invention. Forexample, submersion chilling can employ a peroxycarboxylic acidantimicrobial composition with about 2 to about 100 ppm preferably about2 to about 30 ppm of peroxycarboxylic acid present as a mixture ofperoxyacetic acid and peroxyoctanoic acid, and amounts and additionalingredients as described herein.

[0113] Like submersion chilling, air chilling or cryogenic chillingcools the bird to retain quality of the meat. Air cooling can be lesseffective for decontaminating the bird, as the air typically would notdissolve, suspend, or wash away contaminants. Air chilling with a gasincluding an antimicrobial agent can, however, reduce the burden ofmicrobial, and other, contaminants on the bird. Air chilling typicallyincludes enclosing the carcass in a chamber having a temperature belowabout 5° C. until the carcass is chilled. Air chilling can beaccomplished by applying a cryogenic fluid or gas as a blanket or spray.

[0114] According to the present invention, air chilling can beaccomplished employing a peroxycarboxylic acid antimicrobialcomposition, preferably a composition of the present invention. Forexample, air chilling compositions can include a gaseous or densifiedfluid antimicrobial composition.

[0115] After chilling, the bird can be subjected to additionalprocessing steps including weighing, quality grading, allocation,portioning, deboning, and the like. This further processing can alsoinclude methods or compositions according to the present invention forwashing with mixed peroxycarboxylic acid compositions. For example, itcan be advantageous to wash poultry portions, such as legs, breastquarters, wings, and the like, formed by portioning the bird. Suchportioning forms or reveals new meat, skin, or bone surfaces which maybe subject to contamination and benefit from treatment with anantimicrobial composition. Similarly, deboning a poultry carcass or aportion of a poultry carcass can expose additional areas of the meat orbone to microbial contamination. Washing the deboned poultry carcass orportion with a mixed peroxycarboxylic acid composition canadvantageously reduce any such contamination. In addition, during anyfurther processing, the deboned meat can also come into contact withmicrobes, for example, on contaminated surfaces. Washing the debonedmeat with a mixed peroxycarboxylic acid composition can reduce suchcontamination. Washing can be accomplished by spraying, immersing,tumbling, or a combination thereof, or by applying a gaseous ordensified fluid antimicrobial composition.

[0116] Usable side products of poultry include heart, liver, and gizzard(e.g. giblets), neck, and the like. These are typically harvested laterin processing, and are sold as food products. Of course, microbialcontamination of such food products is undesirable. Thus, these sideproducts can also be washed with a mixed peroxycarboxylic acidcomposition in methods of the present invention. Typically, these sideproducts will be washed after harvesting from the poultry carcass andbefore packaging. They can be washed by submersion or spraying, ortransported in a flume including the antimicrobial composition. They canbe contacted with an antimicrobial composition according to theinvention in a giblet chiller or ice chiller.

[0117] The poultry, poultry product, poultry portion, poultry sideproduct, or the like can be packaged before sending it to moreprocessing, to another processor, into commerce, or to the consumer. Anysuch poultry can be washed with a water based mixed peroxycarboxylicacid antimicrobial composition, which can then be removed (e.g.,drained, blown, or blotted) from the poultry. In certain circumstanceswetting the poultry before packaging is disadvantageous. In suchcircumstances, a gaseous or densified fluid form of the peroxycarboxylicacid antimicrobial composition can be employed for reducing themicrobial burden on the poultry. Such a gaseous composition can beemployed in a variety of processes known for exposing poultry to a gasbefore or during packaging, such as modified atmosphere packaging.

[0118] The advantageous stability of mixed peroxycarboxylic acidcompositions in such methods, which include the presence of poultrydebris or residue, makes these compositions competitive with cheaper,less stable, and potentially toxic chlorinated compounds. Preferredmethods of the present invention include agitation or sonication of theuse composition, particularly as a concentrate is added to water to makethe use composition. Preferred methods include water systems that havesome agitation, spraying, or other mixing of the solution. The poultryproduct can be contacted with the compositions of the inventioneffective to result in a reduction significantly greater than isachieved by washing with water, or at least a 50% reduction, preferablyat least a 90% reduction, preferably at least a 99% reduction in theresident microbial preparation.

[0119] The present methods require a certain minimal contact time of thecomposition with poultry for occurrence of significant antimicrobialeffect. The contact time can vary with concentration of the usecomposition, method of applying the use composition, temperature of theuse composition, amount of soil on the poultry, number of microorganismson the poultry, or the like. Preferably the exposure time is at leastabout 5 to about 15 seconds.

[0120] Spraying Poultry

[0121] A preferred method for washing poultry employs a pressure sprayof the mixed peroxycarboxylic acid composition. During application ofthe spray solution on the poultry product, the surface of the poultryproduct can be moved with mechanical action, preferably agitated,rubbed, brushed, etc. Agitation can be by physical scrubbing of thepoultry product, through the action of the spray solution underpressure, through sonication, or by other methods. Agitation increasesthe efficacy of the spray solution in killing micro-organisms, perhapsdue to better exposure of the solution into the crevasses or smallcolonies containing the micro-organisms. The spray solution, beforeapplication, can also be heated to a temperature of about 15 to 20° C.,preferably about 20 to 60° C. to increase efficacy.

[0122] Application of the material by spray can be accomplished using amanual spray wand application, an automatic spray of poultry productmoving along a production line using multiple spray heads to ensurecomplete contact or other spray means. One preferred automatic sprayapplication involves the use of a spray booth. The spray boothsubstantially confines the sprayed composition to within the parameterof the booth. The production line moves the poultry product through theentryway into the spray booth in which the poultry product is sprayed onall its exterior surfaces with sprays within the booth. After a completecoverage of the material and drainage of the material from the poultryproduct within the booth, the poultry product can then exit the booth ina fully treated form. The spray booth can include steam jets that can beused to apply the antimicrobial compositions of the invention. Thesesteam jets can be used in combination with cooling water to ensure thatthe treatment reaching the poultry product surface is less than 65° C.,preferably less than 60° C. The temperature of the spray on the poultryproduct is important to ensure that the poultry product is notsubstantially altered (cooked) by the temperature of the spray. Thespray pattern can be virtually any useful spray pattern.

[0123] Immersing Poultry

[0124] During processing of the poultry product, the poultry product canbe immersed into a tank containing a quantity of washing solution. Thewashing solution is preferably agitated to increase the efficacy of thesolution and the speed in which the solution reduces micro-organismsaccompanying to the poultry product. Agitation can be obtained byconventional methods, including ultrasonics, aeration by bubbling airthrough the solution, by mechanical methods, such as strainers, paddles,brushes, pump driven liquid jets, or by combinations of these methods.The washing solution can be heated to increase the efficacy of thesolution in killing micro-organisms. It is preferable that the poultryproduct be immersed in the washing solution after the poultry producthave been eviscerated and before any cooling process such as a chillertank or a chill water spray.

[0125] Foam Treating Poultry

[0126] In another alternative embodiment of the present invention, thepoultry product can be treated with a foaming version of thecomposition. The foam can be prepared by mixing foaming surfactants withthe washing solution at time of use. The foaming surfactants can benonionic, anionic or cationic in nature. Examples of useful surfactanttypes include, but are not limited to the following: alcoholethoxylates, alcohol ethoxylate carboxylate, amine oxides, alkylsulfates, alkyl ether sulfate, sulfonates, quaternary ammoniumcompounds, alkyl sarcosines, betaines and alkyl amides. The foamingsurfactant is typically mixed at time of use with the washing solution.Use solution levels of the foaming agents is from about 50 ppm to about2.0 wt-%. At time of use, compressed air can be injected into themixture, then applied to the poultry product surface through a foamapplication device such as a tank foamer or an aspirated wall mountedroamer.

[0127] Gel Treating Poultry

[0128] In another alternative embodiment of the present invention, thepoultry product can be treated with a thickened or gelled version of thecomposition. In the thickened or gelled state the washing solutionremains in contact with the poultry product surface for longer periodsof time, thus increasing the antimicrobial efficacy. The thickened orgelled solution will also adhere to vertical surfaces. The compositionor the washing solution can be thickened or gelled using existingtechnologies such as: xanthan gum, polymeric thickeners, cellulosethickeners or the like. Rod micelle forming systems such as amine oxidesand anionic counter ions could also be used. The thickeners or gelforming agents can be used either in the concentrated product or mixingwith the washing solution, at time of use. Typical use levels ofthickeners or gel agents range from about 100 ppm to about 10 wt-%.

[0129] Light Treating Poultry

[0130] In another alternative embodiment of the present invention, thepoultry product can be exposed to an activating light (or otherelectromagnetic radiation) source following application of the washingsolution. The activating light (or other electromagnetic radiation) canimprove the antimicrobial efficacy of the washing solution. The lightcan be ultraviolet light, infrared light, visible light, or acombination thereof. Other forms of electromagnetic radiation includeradar and microwave.

[0131] Processing Poultry Wash Water

[0132] Washing poultry can employ a large volume of water, or anothercarrier. Poultry wash water can be used more than once (recycled),provided the water can be treated so that it does not transferundesirable microbes to the poultry being washed with the recycled washwater. One way to prevent the transfer of such undesirable microbes, isto reduce the microbial burden of the recycled wash water by adding amixture of peroxycarboxylic acids. For example, if the fluid to berecycled is water-based and lacking any peroxycarboxylic acid, a mixedperoxycarboxylic acid concentrate composition can be added to result inan effective antimicrobial concentration of peroxycarboxylic acid in thefluid to be recycled. Alternatively, if the fluid to be recycled alreadyincludes or has included a peroxycarboxylic acid, a mixedperoxycarboxylic acid concentrate composition can be added to increaseany concentration of peroxycarboxylic acid to an effective antimicrobiallevel. It may be that the peroxycarboxylic acid in the solution to berecycled has been totally depleted, in which case more of the mixedperoxycarboxylic acid composition is added.

[0133] In some circumstances, the water to be recycled includes asubstantial burden of organic matter or microbes. If this is the case,the water may be unsuitable for recycling. However, if the water is tobe recycled, the operator adds a sufficient quantity of the mixedperoxycarboxylic acid composition to provide an effective antimicrobialamount of the peroxycarboxylic acid after a certain amount is consumedby the organic burden or microbes already present. Then, the recycledfluid can be used with antimicrobial effect. Routine testing can beemployed for determining levels of peroxycarboxylic acid, or of organicburden.

[0134] In each case, the method of recycling the poultry wash waterincludes recovering the poultry wash water, adding a mixed compositionof peroxycarboxylic acids, and reusing the poultry wash water forwashing poultry, for example, as described above. The poultry wash watercan be recovered from steps in poultry processing including submersionscalding, dress rinsing, inside-outside bird washing, spray rinsing, andsubmersion chilling. Methods of recovering wash water from these stepsare well-known to those skilled in the poultry washing and/or processingarts. The wash water can also be strained, filtered, diluted, orotherwise cleaned in processed during recycling.

[0135] The present invention may be better understood with reference tothe following examples. These examples are intended to be representativeof specific embodiments of the invention, and are not intended aslimiting the scope of the invention.

EXAMPLES Example 1 Formulas for Peroxyacetic/Peroxyoctanoic AcidMixtures Having Activity Against Microbes Contaminating Poultry

[0136] A preferred antimicrobial concentrate composition of theinvention was formulated as: Material Weight - % Glacial Acetic Acid 55Hydrogen Peroxide 11 HEDP 0.6 Octanoic Acid 4

[0137] The remainder of this concentrate composition was water.

[0138] This concentrate formulation converted to a composition includingperoxy acids during storage for two weeks at generally ambientconditions. In this case, the concentrate composition converted to:Typical Weight Percent of Chemical In Chemical Concentrate 2 WeeksPost-Manufacture Acetic Acid 41 Hydrogen Peroxide 6.2 HEDP 0.6 OctanoicAcid 3.2 Peroxyacetic Acid 12 Peroxyoctanoic Acid 0.8

[0139] The remainder of this concentrate composition was water.

[0140] Such concentrate compositions were diluted to form usecompositions of the present invention, which include: Use Use Use UseSolution 1 Solution 2 Solution 3 Solution 4 Component (ppm) (ppm) (ppm)(ppm) Glacial Acetic 6.8 17 101 985 Acid Deionized Balance BalanceBalance Balance water Peroxyacetic 2 5 30 213 Acid HEDP 0.1 0.3 1.5 13Octanoic Acid 0.5 1.3 8 74 Peroxyoctanoic 0.1 0.3 2 14 Acid Hydrogen 1.02.6 16 110 Peroxide

Example 2 Spray Application of a Mixed Peroxycarboxylic AcidAntimicrobial Composition Reduces Bacterial Pathogen Contamination onPoultry

[0141] Spray application of an antimicrobial composition of theinvention was tested and shown to significantly reduce bacterialpathogen contamination on poultry carcass samples.

[0142] Materials and Methods

[0143] Carcass samples were contaminated with either Salmonellatyphimurium ATCC 13311, Escherichia coli serotype O157:H7 ATCC 43895, orListeria monocytogenes (Petite Scott A) ATCC 49594. Identities of thesebacteria were confirmed based on gram stain reactions, microscopicmorphology and growth characteristics using the appropriate selectivemedium. These strains were grown in culture, by conventional techniques,and adjusted to yield≧10⁷ colony forming units per milliliter (CFU/mL).

[0144] Carcass samples were prepared by inoculating the exterior of athawed 2×2 inch square of chicken skin with 1 mL of a pathogen culture.The square of skin was depressed to form a bowl, and the culture wasallowed to sit in this bowl for 5 min to allow attachment of thebacteria. After attachment, culture was removed from the skin sample andeach sample was placed on a metal stand, epidermal side/inoculated sideup.

[0145] The skin sample was then sprayed with an antimicrobialcomposition described in Example 1. For use, the composition was dilutedto 200±10 ppm total peroxyacid measured as peroxyacetic acid. Thepoultry carcass sample was sprayed with the composition for 15 secondsat 60 psi and room temperature.

[0146] After spraying, the skin samples were aseptically removed andplaced into 20 mL of solution including an agent that inactivates theperoxycarboxylic acids without killing bacteria. The remaining bacteriawere suspended by vortexing and serial dilutions of this solution wereplated for growth of the bacteria. Dilutions were prepared usingphosphate buffered dilution water (PBDW). S. typhimurium and L.monocytogenes plates were incubated at 37° C. for 48 hours. E. coliO157:H7 plates were incubated at 37° C. for 24 hours. For each sample,the number of colony forming units per skin square were calculated.

[0147] Results

[0148] Statistical analysis of the numbers of bacteria on skin samplesdemonstrated that spray application of the antimicrobial composition ofthe invention significantly reduced levels of Salmonella typhimurium,Escherichia coli, and Listeria monocytogenes. These results areillustrated in Table 1 below. TABLE 1 Log Reduction of Bacteria LevelsAfter Spraying With a Mixed Peroxycarboxylic Acid Antimicrobial AgentPeroxycarboxylic Acid Bacteria Antimicrobial Agent Salmonellatyphimurium 0.8 Escherichia coli 3.2 Listeria monocytogenes 2.1

[0149] Conclusion

[0150] Spray application of an antimicrobial composition of theinvention significantly reduces bacterial pathogen contamination onpoultry carcass samples.

Example 3 Submersion Application of a Mixed Peroxycarboxylic AcidAntimicrobial Composition Reduces Bacterial Pathogen Contamination onPoultry

[0151] Submersion application of an antimicrobial composition of theinvention was tested and shown to significantly reduce bacterialpathogen contamination on poultry carcass samples.

[0152] Materials and Methods

[0153] Bacteria were selected and cultured generally as described inExample 2 above, except that the bacteria were diluted to ≧10⁶ colonyforming units per milliliter (CFU/mL) for inoculation of carcasssamples.

[0154] Carcass samples were prepared by thawing frozen chicken wings andlivers. The thawed samples were inoculated by submersing in thesuspension of bacteria. Other surfaces were not inoculated. Theinoculated surface was marked for identification and allowed to drainand sit for 5 min. at room temperature.

[0155] The antimicrobial composition was as described in Example 1. Theuse solution was diluted to 30 ppm total peroxyacid measured asperoxyacetic acid. Antimicrobial agent was applied by submersing theinoculated and uninoculated surfaces for 60 min in the same 2 liters ofa use solution of the antimicrobial agent at 4° C. The same experimentwas performed using water without the antimicrobial agent.

[0156] After submersing for 60 min., the inoculated and uninoculatedsurfaces were removed from the antimicrobial agent use solution or waterand gently agitated in 100 mL of solution including an agent thatinactivates the peroxycarboxylic acids without killing bacteria.Removing and analyzing the uninoculated surfaces was necessary tomeasure cross contamination of bacteria from the inoculated surfaces.Serial dilutions of this solution were plated for growth of the bacteriaas described above in Example 2. Cross contamination log reduction wascalculated by subtracting the Log number of bacteria on uninoculatedsurfaces submersed in the antimicrobial use solution from the Log numberof surviving bacteria on uninoculated surfaces submersed in water.

[0157] Results

[0158] Statistical analysis of the numbers of bacteria on carcasssamples demonstrated that submersion application of the antimicrobialcomposition of the invention significantly reduced levels of Salmonellatyphimurium, Escherichia coli, and Listeria monocytogenes. These resultsare illustrated in Tables 2 and 3 below. TABLE 2 Log Reduction ofBacteria Levels After Submersing a Chicken Wing in a MixedPeroxycarboxylic Acid Antimicrobial Agent Peroxycarboxylic Acid BacteriaAntimicrobial Agent Salmonella typhimurium 0.3 Escherichia coli 1.2Listeria monocytogenes 1.3

[0159] TABLE 3 Log Reduction of Bacteria Levels After Submersing aChicken Liver in a Mixed Peroxycarboxylic Acid Antimicrobial AgentPeroxycarboxylic Acid Bacteria Antimicrobial Agent Salmonellatyphimurium 0.5 Escherichia coli 0.9 Listeria monocytogenes 0.6

[0160] Conclusion

[0161] Submersion application of an antimicrobial composition of theinvention significantly reduces bacterial pathogen contamination onpoultry carcass samples.

Example 4 Reduction of Spoilage or Decay Causing Bacteria on PoultryCarcasses

[0162] This study determined that a mixed peroxycarboxylic acidantimicrobial composition in water used for spraying or submersingeviscerated chicken carcasses provided a reduction of total aerobicbacteria, coliform bacteria, and Escherichia coli.

[0163] Materials and Methods

[0164] Freshly collected chicken carcasses were subjected to sprayingwith or submersion in an antimicrobial composition described in Example1 above. Use solutions, spray time and pressure, and submersiontemperature and duration were as described in Examples 2 and 3 above.Some carcasses were both sprayed and submersed. Control carcasses wereuntreated.

[0165] Each carcass was then placed in a collection bag using freshlygloved hands. In the bag, the carcass was rinsed with Butterfield'sPhosphate Diluent (BPD) and the BPD solution collected for microbiologytesting. Known, standard procedures for quantifying total aerobicbacteria, coliform bacteria, and Escherichia coli were employed.

[0166] Results

[0167] Statistical analysis of the numbers of bacteria on carcasssamples demonstrated that spray, submersion, and combination applicationof the antimicrobial composition of the invention significantly reducedlevels of total aerobic bacteria, coliform bacteria, and Escherichiacoli. These results are illustrated in Table 4 below. TABLE 4 LogReduction of Bacteria Levels After Treating a Chicken Carcass with aMixed Peroxycarboxylic Acid Antimicrobial Agent Application AerobicPlate Count E. coil Count Coliform Count Spray 0.62 0.84 0.64 Submersion1.21 1.37 1.27 Spray and 1.33 1.44 1.31 Submersion

[0168] Conclusion

[0169] Spray, submersion, and spray and submersion application of anantimicrobial composition of the invention significantly reducescontamination by spoilage or decay causing bacteria on poultrycarcasses.

[0170] It should be noted that, as used in this specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferents unless the content clearly dictates otherwise. Thus, forexample, reference to a composition containing “a compound” includes amixture of two or more compounds. It should also be noted that the term“or” is generally employed in its sense including “and/or” unless thecontent clearly dictates otherwise.

[0171] All publications and patent applications in this specificationare indicative of the level of ordinary skill in the art to which thisinvention pertains.

[0172] The invention has been described with reference to variousspecific and preferred embodiments and techniques. However, it should beunderstood that many variations and modifications may be made whileremaining within the spirit and scope of the invention.

We claim:
 1. A method of reducing a microbial population on poultryduring processing comprising: applying to the poultry during processinga mixed peroxycarboxylic acid antimicrobial composition in an amount andtime sufficient to reduce the microbial population.
 2. The method ofclaim 1 wherein the poultry being processed comprises chicken, turkey,ostrich, game hen, squab, guinea fowl, pheasant, duck, goose, emu, or acombination thereof.
 3. The method of claim 1, comprising applying themixed peroxycarboxylic acid composition by submersing the poultry. 4.The method of claim 3, comprising applying the mixed peroxycarboxylicacid composition by submersion scalding, by submersion chilling, byhydro-cooling or chilling, tumble immersion, or by a combinationthereof.
 5. The method of claim 3, comprising applying the mixedperoxycarboxylic acid composition for a duration and at a concentrationselected to yield visually imperceptible darkening of subcutaneousbruises, pooled blood, or a combination thereof.
 6. The method of claim1, comprising applying the mixed peroxycarboxylic acid composition byrinsing or spraying the poultry.
 7. The method of claim 6, comprisingapplying the mixed peroxycarboxylic acid composition with ade-feathering picker, by inside-outside bird washing, by dress rinsing,by spray rinsing, or a combination thereof.
 8. The method of claim 1,comprising applying the mixed peroxycarboxylic acid composition to awhole poultry carcass.
 9. The method of claim 8, comprising applying themixed peroxycarboxylic acid composition to a poultry carcass that hasbeen subjected to stunning, bleeding, scalding, picking, singeing, or acombination thereof.
 10. The method of claim 1, comprising applying themixed peroxycarboxylic acid composition to one or more dismembered partsof a poultry carcass.
 11. The method of claim 10, comprising applyingthe mixed peroxycarboxylic acid composition to a poultry carcass thathas been subjected to beheading, removing feet, eviscerating,neck-cropping, portioning, or a combination thereof.
 12. The method ofclaim 11, comprising applying the mixed peroxycarboxylic acidcomposition to a poultry leg, thigh, breast quarter, wing, orcombination thereof of a poultry that has been subjected to portioning.13. The method of claim 10, comprising applying the mixedperoxycarboxylic acid composition to a poultry that has also beensubjected to boning.
 14. The method of claim 13, comprising applying themixed peroxycarboxylic acid composition to a boned poultry leg, thigh,breast, wing, or combination thereof.
 15. The method of claim 1,comprising applying the mixed peroxycarboxylic acid composition by airchilling.
 16. The method of claim 15, wherein the mixed peroxycarboxylicacid composition comprises peroxyacetic acid and peroxyoctanoic acid.17. The method of claim 15, wherein air chilling comprises applying agaseous or densified fluid antimicrobial composition. 18 The method ofclaim 1, further comprising exposing the poultry to activated light. 19.The method of claim 18, wherein the activated light comprisesultraviolet light, infrared light, visible light, or a combinationthereof.
 20. The method of claim 1, wherein the mixed peroxycarboxylicacid antimicrobial composition comprises: at least about 2 ppm of one ormore mono- or di-peroxycarboxylic acids having up to 6 carbon atoms; andat least 0.5 ppm of one or more carboxylic acids having up to 12 carbonatoms.
 21. The method of claim 20, wherein the mixed peroxycarboxylicacid composition comprises one or more peroxycarboxylic acids havingfrom 2 to 6 carbon atoms and a peroxycarboxylic acid having from 7 to 12carbon atoms.
 22. The method of claim 21, wherein the mixedperoxycarboxylic acid composition comprises peroxyacetic acid andperoxyoctanoic acid.
 23. The method of claim 22, wherein the mixedperoxycarboxylic acid antimicrobial composition further comprisesstabilizing agent, wetting agent, hydrotrope, thickener, foaming agent,acidifier, pigment, dye, surfactant, or a combination thereof.
 24. Themethod of claim 1, wherein the microbial population is the result ofcontamination by fecal matter or digestive tract content.
 25. The methodof claim 24 wherein the microbial population is reduced in a continuousonline process.
 26. The method of claim 1, further comprising, afterapplying: recovering the applied mixed peroxycarboxylic acidantimicrobial composition; and adding to the recovered composition asufficient amount of a mixture of peroxycarboxylic acids to yield arecycled mixed peroxycarboxylic acid antimicrobial composition.
 27. Themethod of claim 26, further comprising applying the recycled compositionto poultry during processing.
 28. The method of claim 26, wherein themixture of peroxycarboxylic acids comprises peroxyacetic acid andperoxyoctanoic acid.
 29. The method of claim 28, wherein the mixture ofperoxycarboxylic acids comprises about 30 to about 60 weight-% aceticacid, about 1 to about 15 weight-% octanoic acid, about 2 to about 12weight-% hydrogen peroxide, about 6 to about 16 weight-% peroxyaceticacid, and about 0.1 to about 5 weight-% peroxyoctanoic acid, and about0.1 to about 2 weight-% chelating agent.
 30. The method of claim 26,wherein the recycled mixed peroxycarboxylic acid antimicrobialcomposition comprises: at least about 2 ppm of one or more mono- ordi-peroxycarboxylic acids having up to 6 carbon atoms; and at least 0.5ppm of one or more carboxylic acids having up to 12 carbon atoms. 31.The method of claim 30, wherein the recycled mixed peroxycarboxylic acidcomposition comprises one or more peroxycarboxylic acids having from 2to 6 carbon atoms and a peroxycarboxylic acid having from 7 to 12 carbonatoms.
 32. A method of reducing a microbial population on poultry duringprocessing comprising: contacting the poultry during processing with agaseous or densified fluid peroxycarboxylic acid antimicrobialcomposition in an amount and time sufficient to reduce the microbialpopulation.
 33. A method of recycling water previously applied topoultry, the method comprising: recovering a mixed peroxycarboxylic acidantimicrobial composition previously applied to poultry; and adding tothe recovered composition a sufficient amount of a mixture ofperoxycarboxylic acids to yield a recycled mixed peroxycarboxylic acidantimicrobial composition.
 34. The method of claim 33, furthercomprising applying the recycled composition to poultry duringprocessing.
 35. The method of claim 33, wherein the mixture ofperoxycarboxylic acids comprises peroxyacetic acid and peroxyoctanoicacid.
 36. The method of claim 35, wherein the mixture ofperoxycarboxylic acids comprises about 30 to about 60 weight-% aceticacid, about 1 to about 15 weight-% octanoic acid, about 2 to about 12weight-% hydrogen peroxide, about 6 to about 16 weight-% peroxyaceticacid, and about 0.1 to about 5 weight-% peroxyoctanoic acid, and about0.1 to about 2 weight-% chelating agent.
 37. The method of claim 33,wherein the recycled mixed peroxycarboxylic acid antimicrobialcomposition comprises: at least about 2 ppm of one or more mono- ordi-peroxycarboxylic acids having up to 6 carbon atoms; and at least 0.5ppm of one or more carboxylic acids having up to 12 carbon atoms. 38.The method of claim 37, wherein the recycled mixed peroxycarboxylic acidcomposition comprises one or more peroxycarboxylic acids having from 2to 6 carbon atoms and a peroxycarboxylic acid having from 7 to 12 carbonatoms.
 39. The method of claim 33, wherein the composition waspreviously applied by a carcass wash or rinse.
 40. The method of claim33, wherein the composition was previously applied by an inside-outsidebird wash.
 41. An antimicrobial concentrate composition comprising: acombination of peroxyacetic acid and peroxyoctanoic acid effective forreducing the microbial burden on a surface of poultry; the combinationcomprising about 30 to about 60 weight-% acetic acid, about 1 to about15 weight-% octanoic acid, about 2 to about 12 weight-% hydrogenperoxide, about 6 to about 16 weight-% peroxyacetic acid, and about 0.1to about 5 weight-% peroxyoctanoic acid, and about 0.1 to about 2weight-% chelating agent.
 42. The antimicrobial concentrate compositionof claim 41, further comprising stabilizing agent, wetting agent,hydrotrope, thickener, foaming agent, acidifier, pigment, dye,surfactant, or a combination thereof.
 43. The antimicrobial concentratecomposition of claim 42, comprising about 40 weight-% acetic acid, about3 weight-% octanoic acid, about 6 weight-% hydrogen peroxide, about 10weight-% peroxyacetic acid, and about 0.8 weight-% peroxyoctanoic acid,and about 0.6 weight-% chelating agent.
 44. An antimicrobial usecomposition comprising: a combination of peroxyacetic acid andperoxyoctanoic acid effective for reducing the microbial burden on asurface of poultry; the combination comprising about 5 to about 1000 ppmacetic acid, about 0.5 to about 100 ppm octanoic acid, about 1 to about200 ppm hydrogen peroxide, about 2 to about 300 ppm peroxyacetic acid,and about 0.1 to about 20 ppm peroxyoctanoic acid, and about 3 to about30 ppm chelating agent.
 45. The antimicrobial use composition of claim44, further comprising stabilizing agent, wetting agent, hydrotrope,thickener, foaming agent, acidifier, pigment, dye, surfactant, or acombination thereof.
 46. An antimicrobial concentrate compositioncomprising: a combination of peroxyacetic acid and peroxyoctanoic acideffective for reducing the microbial burden on a surface of poultry; thecombination comprising an equilibrium mixture resulting from acomposition of about 40 to about 70 weight-% acetic acid, about 2 toabout 20 weight-% octanoic acid, and about 5 to about 15 weight-%hydrogen peroxide, and about 0.3 to about 1 weight-% chelating agent.47. The antimicrobial concentrate composition of claim 46, comprising anequilibrium mixture resulting from a composition of about 55 weight-%acetic acid, about 11 weight-% hydrogen peroxide, about 0.6 weight-%chelating agent, and about 4 weight-% octanoic acid.
 48. Anantimicrobial concentrate composition comprising: a combination ofacetic acid, octanoic acid, and hydrogen peroxide effective forproducing an equilibrium mixture that reduces the microbial burden on asurface of poultry; the combination comprising about 40 to about 70weight-% acetic acid, about 2 to about 20 weight-% octanoic acid, andabout 5 to about 15 weight-% hydrogen peroxide, and about 0.3 to about 1weight-% chelating agent.
 49. The antimicrobial concentrate compositionof claim 48, further comprising stabilizing agent, wetting agent,hydrotrope, thickener, foaming agent, acidifier, pigment, dye,surfactant, or a combination thereof.
 50. The antimicrobial concentratecomposition of claim 48, comprising about 55 weight-% acetic acid, about11 weight-% hydrogen peroxide, about 0.6 weight-% chelating agent, andabout 4 weight-% octanoic acid.